chromium/src/third_party/blink/web_tests/fast/parser/xml-iframe-document-open.html

<script>
  // This test is based on this clusterfuzz report: https://clusterfuzz.com/testcase?key=5195085559955456
  if (window.testRunner) {
    testRunner.dumpAsText();
    testRunner.waitUntilDone();
  }
  function moveIframe(svgDoc) {
    const iframe = document.createElement('iframe');
    svgDoc.documentElement.appendChild(iframe);
    iframe.contentWindow.onunload = () => {
      // This unload handler will be called when the XML parser encounters a
      // parsing error on the <element> tag to replace the frame with an error page.
      // The logic to create the error page didn't perfectly account for the opening
      // and closing of the original document here.
      document.write();
      document.close();
      document.body.appendChild(document.createTextNode('PASS'));
      if (window.testRunner)
        testRunner.notifyDone();
    }
  }
  const iframe = document.createElement('iframe');
  iframe.src = 'resources/xml-parse-error.xml';
  document.documentElement.appendChild(iframe);
</script>